Current Oven Wire

[dball]

I have recently upgraded my oven from a small built in oven to a freestanding 'stoves' oven. Apparently this could need up to 4.9kwh. I am finding it hard to work out if the current wire coming into the kitchen is big enough (6mm or likewise)... Photos attached (hopefully).. I know I need to attach this wire to a 45amp oven switch first, but I need to know if this wire is good enough, or if we need to change the whole wire from the fuse box to the kitchen. Many Thanks, and hope you understand the problem.

Untitled

• dball
• 5 Apr 2015
• 1

Untitled

• dball
• 5 Apr 2015
• 1

Untitled

• dball
• 5 Apr 2015
• 1

 

[AndyPRK]

Looks like 1.5mm or 2.5mm to me

 

[PrenticeBoyofDerry]

The pictures show solid cables, not stranded! So that would suggest the cables are no greater than 2.5mm.

Do you have your cooker/oven spec, so can work out what is required. But the instruction should tell you.

On the bare facts, if your stove/cooker requires 4.9kw, even calculating diversity into it, would mean a 13A socket would be borderline.
But 2.5mm cable can handle 27A (providing no derating).
So even on full load you have about 21A demand.
So very likely if 2.5mm cable then a 16A, 20A or 25A protective device would be suitable. I assume this circuit is dedicated to the cooker and not part of another circuit supplying power elsewhere?

 

[ericmark]

If 2.5mm it will depend on how it is supplied. 21.3A (4.9kW) is just over the 21A quoted for Reference Method 100# (above a plasterboard ceiling covered by thermal insulation not exceeding 100 mm in thickness) but close enough not to really matter. If supplied from a dedicated 20A MCB/RCBO it could be enough.

However it is rare to find dedicated circuits other than for immersion heater in a house using 2.5mm cable. Often when one finds 2.5mm it is a fused or unfused spur from a larger circuit often the ring final. With the latter even a 3kW fixed appliance should not be connected. (fixed refers to weight and a washing machine, tumble drier, dishwasher and cooker unless they are pulled to centre of floor as with old top loaders would be considered fixed).

So likely you will need a better supply but the info given is not enough to realy say either way.

 

[JohnW2]

If 2.5mm it will depend on how it is supplied. 21.3A (4.9kW) is just over the 21A quoted for Reference Method 100# ....

Using your 21.3A figure (based on 230V), that would actually be 13.39A after diversity.

In fact, the 4.9kW will almost certainly be quoted at 240V, which would mean a current of about 19.6A at 230V - corresponding to after-diversity current of about 12.9A. I therefore suspect that this cooker was designed to be able to run off a 13A plug.

However it is rare to find dedicated circuits other than for immersion heater in a house using 2.5mm cable. Often when one finds 2.5mm it is a fused or unfused spur from a larger circuit often the ring final.

That's true. In terms of the after-diversity currents, 2.5mm² cable on a 20A (or even 16A) MCB ought to be fine, and that would remain true more-or-less regardless of installation method. However, as you say, the fact that it is wired in 2.5mm suggests that it may not be a dedicated circuit, in which case it would be questionable as to whether it would be desirable to use it for a cooker. Having said that, countless ~13A (after diversity) cookers are plugged into ring or radial finals.

The OP really needs the advice of an electrician, who could ascertain exactly where that supply is coming from, and then advise accordingly.

Kind Regards, John

 

[JohnD]

When you say "oven" do you mean "oven" or do you mean "cooker?"

 

[JohnW2]

When you say "oven" do you mean "oven" or do you mean "cooker?"

(despite the fact that I described it as a cooker in my recent post!!) One assumes almost certainly just an oven. If there were a hob involved, it's very unlikely that the total power would only be 4.9kW.

Kind Regards, John

 

[AndyPRK]

Op called it a freestanding stoves oven.

I had assumed it would have some hot plates.

 

[JohnW2]

Op called it a freestanding stoves oven. I had assumed it would have some hot plates.

One might think so, from the words. However, as I said, I find it hard to see that any usable oven+hob could add up to as little as 4.9kW (unless that is an after-diversity figure!).

dball: What is the make and model of this new stove?

Edit: Ah! I think a "'stoves oven" is probably (just) an oven, manufactured by the company Stoves !

Kind Regards, John

 

[PrenticeBoyofDerry]

Edit: Ah! I think a "'stoves oven" is probably (just) an oven, manufactured by the company Stoves !

Nailed it!

 

[JohnW2]

Edit: Ah! I think a "'stoves oven" is probably (just) an oven, manufactured by the company Stoves !

Nailed it!

I thought I had, but I've just looked at the Stoves website and they don't seem to do freestanding ovens - only built-in ovens or freestanding cookers! So I think we're back to needing to know the make/model from the OP!

Kind Regards, John

 

[ban-all-sheds]

I have recently upgraded my oven from a small built in oven to a freestanding 'stoves' oven. Apparently this could need up to 4.9kwh.

That's a useless figure. It tells you how much energy the cooker needs to carry out a/some standard cooking task(s).

It does not tell you how much it draws at any point in time. You get the same 4.9kWh from 21.3A for 1 hour and 1,278.3A for 1 minute.

To design the circuit you need to know the actual power draw of the cooker.

 

[ban-all-sheds]

Op called it a freestanding stoves oven.

I had assumed it would have some hot plates.

It could be dual-fuel.

 

[ericmark]

Free standing cooker

can be designed to work on 13A. OK today looks more like this

but still the same idea it is designed to work on 13A and simply plug in but rating is approx 3kW not 4.9kW and I would not think it refers to this type.

However using the hot plate method there are some cookers which do still use only 20A the hot plate is never switched off just a insulated hinged cover is brought down over the hot plate when not in use and energy is stored in the cast iron plate they are often built on the stile of the old range cooker.

But 3kW = 13A and 4.9kW = over 20A so using a FCU is not really an option.

 

[ban-all-sheds]

But 3kW = 13A and 4.9kW = over 20A so using a FCU is not really an option.

4.9kWh

9A for 25 minutes = ______